Packaging of electronic components such as integrated circuits routinely finds hundreds of circuit functions within a volume that heretofore was occupied by a single element, such as a resistor, capacitor, or inductor. As a result, the physical spacings of the elements have become quite small, and the elements themselves relatively fragile and susceptible to damage from transient signals caused by a host of phenomena met in the practical environment of use. Induced voltages from short circuits, lightning strikes, static electric charges built up on individuals or equipment, all may find their way into components and destroy the elements thereof to cause a lack of function. This failure, resulting from electrical over stress (EOS) has led to a host of circuit protection devices, typically mounted on the same circuit board upon which the components are carried. These devices have included electrical fuses that open up responsive to IR heating, typically relatively slow in action, as well as varistors, zener diodes, and a host of other devices including spark gap devices, thin film devices, and LC filters have been employed. U.S. Pat. No. 4,729,752 discloses a transient suppression device in the form of a back-to-back diode mounted on a substrate that fits within an electrical connector. This device suppresses voltages outside a specified level as they are conducted through the signal conductors of the connector and incorporation into the connector saves valuable board space.
With respect to the foregoing, all of the protection devices require either a special installation and handling or an alteration of existing designs of connectors in order to accommodate the EOS devices. Many of the prior art EOS elements are bulky, slow to respond, and expensive to acquire and install to provide protection to components upon boards. Accordingly, it is an object of the present invention to provide an EOS device that may be fitted onto electrical connectors to provide board mounted component protection against unwanted transients.
It is a further object to provide an EOS device that can be utilized with existing connector designs, without significant alteration of such connectors.
It is an additional object to provide a cost effective, readily employed EOS device and connector to provide component protection.
It is still a further object to provide, in combination, an EOS device and an electrical connector of improved features.